* THE ORIGIN OF SPECIES' 87 



detailed treatises on the Variation of Animals and Plants 

 under Domestication, on the Effects of Cross and Self- 

 Fertilisation, and on the Descent of Man and Sexual 

 Selection. But the immense and unexpected vogue of 

 his first volume, the almost immediate revolution which 

 it caused in biological and general opinion, and the all 

 but universal adhesion to his views of all the greatest 

 and most rising naturalists, to a great extent saved him 

 the trouble of carrying out in full the task he had 

 originally contemplated as necessary. Younger and 

 less occupied labourers took part of the work off their 

 leader's hands ; the great chief was left to prosecute his 

 special researches in some special lines, and was relieved 

 from the necessity of further proving in minuter detail 

 what he had already proved with sufficient cogency to 

 convince all but the wilfully blind or the hopelessly 

 stupid. 



The extraordinary and unprecedented success of the 

 ' Origin of Species ' is the truest test of the advance it 

 made upon all previous evolutionary theorising. Those 

 who had never been convinced before were now con- 

 vinced by sheer force of reasoning ; those who believed 

 and those who wavered had their faith confirmed into 

 something like the reposeful calm of absolute certitude. 



Let us consider, therefore, what exactly were the 

 additions which Charles Darwin offered in his epoch- 

 making work to the pre-existing conceptions of evolu- 

 tionists. 



In 1852, seven years before the publication of 

 Darwin's masterpiece, Mr. Herbert Spencer wrote as 

 follows in an essay in the 'Leader' on creation and 

 evolution. The expressions of so profound and philo- 



